Unconventional p–d Hybridization Interaction in PtGa Ultrathin Nanowires Boosts Oxygen Reduction Electrocatalysis

Alloying 3d transition metals with Pt has been discovered as an effective strategy to boost the catalytic activity in oxygen reduction reaction (ORR), which, however, often raises the insufficient catalyst durability issue due to rapid leaching of the 3d metal elements. To overcome this issue and realize enhancements in both the activity and the durability properties, here we report a new catalytic structure based on PtGa ultrathin alloy nanowires (NWs), which feature an unconventional strong p–d hybridization interaction. Relative to commercial Pt catalyst, the optimum Pt4.31Ga NWs catalyst exhibited 10.5- and 12.1-fold enhancement in the ORR mass activity and specific activity, respectively. Particularly, the Pt4.31Ga NWs catalyst showed only 15.8% loss in the mass activity after 30 000 cycles of durability test, as compared to a big decrease of 79.6% for the commercial Pt catalyst. Our mechanistic studies find a strong p–d hybridization interaction between Ga and Pt that accounts for the improved ORR performance via synergistically optimizing the surface electronic structure, enhancing the oxidation resistance of Pt, and suppressing the leaching of lattice Ga. We believe this work provides new perspectives to design active and durable electrocatalysts toward ORR.